The M-1 tank used by U.S. military forces is driven by a turbine engine. The air cleaner for this turbine engine is an upright box-like structure having two types of air cleaning devices therein. In the upper section of the box there is a bank of small inertial separator tubes (approximately 400 tubes). These tubes remove more than 90 percent of the dust in the airstream supplied to the box. In the lower section of the box there are two air filter panels formed of pleated fabric material (paper); dust particles in the partially cleaned air stream are trapped on the upstream faces of the pleated fabric material. Sufficient dust is collected by the filter panels to bring the overall collection efficiency of the air cleaner above 99%.
For proper operation the inertial separation tubes must be exposed to a scavenger suction force (in order to pull dust concentrates out of the tubes and deliver same to a point outside the vehicle). Conventionally the scavenger suction force is provided by a special duct containing a motor-operated fan.
The turbine engines require large quantities of air. As a consequence the scavenger fan handles relatively large air quantities. Erosion of the fan blades is a maintenance problem.
The present invention relates to an aspirator mechanism that can be used in place of the scavenger fan heretofore used. The aspirator mechanism preferably comprises a flat rectangular chamber located on the undersurface of the engine exhaust duct just downstream from a gas-turning zone at the engine exhaust opening. A suitable passage structure extends from the filter box to the flat chamber.
The flat chamber is connected to the engine exhaust duct via a slot-like orifice extending entirely across the duct width. The stream of gas flowing through the exhaust duct applies a vacuum force to the orifice, to thereby draw dust-laden air out of the aforementioned chamber into the gas stream exiting from the engine.
The chamber and aspirator orifice are located at the inside turn of a gas-turning elbow section in the exhaust duct, so as to take advantage of inertia forces associated with the gas turn action. Dust-laden air is moved into an otherwise turbulent zone (at the inside of the turn) which would generate flow losses and back pressure on the engine. The aspirator will not improve engine performance, but it will perform its dust-removal function with relatively minor negative effects on engine performance, especially when the engine is operating at low power levels.